When I worked Computer Main Frame AIr Conditioning and Backup Power, the Rule of thumb was not to go over 80% of Capacity on Batteries, Generators, Converters and Inverters “UPS” unless you were asking for a World of trouble. Also I would avoid Inverters, and dual batteries just due to the added problems with them. There’s plenty of small DC Pumps out there to use. You don’t need 100% Water Flow unless you are out for a week or more, then it’s a True Syn-Wave Generator.